Alanylglutamine is a dipeptide containing two amino acids, alanine and glutamine, and is immediately degraded into alanine and glutamine in the body (refer to “Clinical Science”, 1988, Vol. 75, No. 5, p. 463-8). The action of glutamine is known to have many effects on physiological functions, such as the regulation of skeletal muscle protein metabolism, repair of small intestine mucosa, and improvement of immunofunction, and it has been reported that the effects of alanine on physiological functions include an action to suppress blood sugar levels in diabetes patients (refer to “L-Alanyl-L-Glutamine”, Kyowa Hakko Co., Ltd., 2006, p. 1).
It has also been reported that alanylglutamine has an action to enhance vision performance (refer to WO 2013/129700 A1).
Alanylglutamine is superior in heat stability and solubility in aqueous solutions compared to glutamine, which has low-solubility and poor stability (refer to “L-Alanyl-L-Glutamine”, Kyowa Hakko Co., Ltd., 2006, p. 3), and is used in parenteral nutritional agents as a glutamine supply source.
Nonetheless, alanylglutamine is not known to have an action to enhance ability to concentrate.